Lung cancer is a cancer that starts in the lung. More than 1.3 million people die every year due to lung cancer. The primary causes of lung cancer are smoking, radon gas, asbestos, genetics, etc. and smoking is known as the biggest cause of lung cancer.
More specifically, lung cancer is classified into small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC). The NSCLC is the most common cancer that accounts for approximately 80% of all lung cancer cases and it is divided into adenocarcinoma, squamous cell carcinoma, and large cell carcinoma. Because there are differences in histological characteristics as well as prognoses and treatments depending on types of lung cancer, an accurate diagnosis is important. In case of NSCLC, despite the recent development of cancer treatments, the 10-year survival rate for lung cancer is less than 10%, which is very low. This is because it is difficult to diagnose lung cancer in most of patients even with seriously advanced NSCLC.
Typically, early lung cancer does not have any symptoms at all and even after it progresses to some degree, it just has simple symptoms such as cough and expectoration, which are just similar to common cold. Therefore, it is very difficult to diagnose through common medical examinations by interviews, and patients with lung cancer have different symptoms depending on a location where the lung cancer starts. The common symptoms of lung cancer include coughing, blood expectoration or coughing up blood, shortness of breath, chest pain, husky voice, superior vena cava syndrome, bone pain, fracture, headache, nausea and vomiting, but at the time when patients themselves start to recognize such symptoms, the lung cancer may have already progressed to an advanced stage.
Accordingly, at the present time, early detection of lung cancer is the best way to increase survivability of patients.
The best way to detect lung cancer earlier is periodic medical examinations. Upon such medical examinations, whether patients have lung cancer or not can be determined by collecting biospecimens derived from their bodies, such as their blood and urine. As such, an indicator that can be used to identify any change in a body by using protein, nuclear acid, metabolite, etc., included in a biospecimen refers to a biomarker.
For example, according to the conventional biomarker techniques such as Korean Patent Registration No. 10-1463588, it is disclosed that biomarkers consisting of AIAT, IGF-1, RANTES, and TTR are used to diagnose lung cancer earlier. If it is possible diagnose lung cancer with better classification ability than the conventional ones, it may be favorable from the aspects of the time, costs and effects of confirming lung cancer.